1. Field of the Invention
The present invention relates to supports for supporting motorcycle engines on a motorcycle frame, and more particularly to a motorcycle engine stabilizer structure for reducing the amplitude of vibration of such engines.
2. Description of the Related Art
Because motorcycle engines are usually either one cylinder or two cylinder engines, they inherently exhibit vibration when in operation. Although a certain level of vibrations can readily be tolerated, if the vibration amplitude or frequency example, on some engines high amplitude engine vibrations during operation can cause the cylinder head bolts to become loosened, thereby reducing engine power output by permitting leakage of fuel-air mixture from the cylinders and thereby reducing the compression pressure within the cylinders.
Various approaches have been conceived and attempted in the past to support such engines on a motorcycle frame in such a way that excessive vibrations are not produced. In that regard, motorcycle engines often have a gearbox, or power transmission, that is formed integrally with the engine and its crankcase, in order to save space. The mounting points for mounting the engine-gearbox assembly are generally on forward and rear portions of the gearbox. As a result, the cylinders, which extend upwardly and outwardly from the gearcase, and the heads of which are spaced some distance from the gearbox mounting points, often vibrate from side to side, relative to the motorcycle frame.
Various attempts have been made in the past in an effort to reduce the side to side vibrations of such engines. For example, in U.S. Pat. No. 4,323,135, which issued on Apr. 6, 1982, to Nobuyoshi Tominaga et al., there is disclosed a motorcycle engine and crankcase assembly in which the engine is a two cylinder, V-type engine, and wherein the respective engine cylinder heads are connected with the motorcycle frame by brackets that extend upwardly from the cylinder heads and pass through resilient bushings.
Another approach toward mounting an engine on a motorcycle in such a way that the engine is more securely supported to avoid lateral vibrations is shown in U.S. Pat. No. 4,550,698, which issued on Nov. 5, 1985, to Reinhard Konneker. As disclosed in that patent, each cylinder head includes a central support core to which a holding member is joined, and which extends to and is connected with the motorcycle frame. The holding member is in the form of a yoke-type bracket that is securely connected with the support core at one end and is bolted to the underside of the frame at its opposite end.
Although the provision of such mounting arrangements as are disclosed in the Tominaga et al. and Konneker patents identified above would appear to provide a solution to the excessive vibration problem, the structures disclosed in those patents cannot readily be incorporated onto motorcycles that lack supports that extend from the engine cylinders to the frame, and that lack corresponding connection points on the frame. Thus, one having a motorcycle that did not originally include such mounting arrangements would find it very difficult and cumbersome to attempt to adapt such solutions to an existing motorcycle. Additionally, neither of the Tominaga et al. or Konneker devices is adjustable and thus neither device can be applied to other motorcycles having different cylinder head to frame spacings.
It is therefore an object of the present invention to provide a stabilizer arrangement for motorcycle engines, wherein the stabilizer can be readily incorporated on existing motorcycles that did not originally contain connection points for such arrangements.
It is a further object of the present invention to provide an easily inserted stabilizer device that can be adapted to fit a wide variety of motorcycles having different engine cylinder head to motorcycle frame spacings.
It is a still further object of the present invention to provide a motorcycle engine stabilizer device that extends between the cylinder heads and the frame, and that is of adjustable length to change the vibration characteristics of the engine.
It is another object of the present invention to provide a simple, relatively inexpensive stabilizer device that does not require unusual tools for its installation.